# Copyright (c) 2019-present, Facebook, Inc.
# All rights reserved.
#
# This source code is licensed under the license found in the
# LICENSE file in the root directory of this source tree.
#
def f_gold ( a , n ) :
    cnt = dict ( )
    ans = 0
    pre_sum = 0
    for i in range ( n ) :
        ans += ( i * a [ i ] ) - pre_sum
        pre_sum += a [ i ]
        if ( a [ i ] - 1 ) in cnt :
            ans -= cnt [ a [ i ] - 1 ]
        if ( a [ i ] + 1 ) in cnt :
            ans += cnt [ a [ i ] + 1 ]
        if a [ i ] not in cnt :
            cnt [ a [ i ] ] = 0
        cnt [ a [ i ] ] += 1
    return ans


#TOFILL

if __name__ == '__main__':
    param = [
    ([2, 8, 12, 19, 23, 23, 26, 39, 54, 56, 57, 57, 73, 78, 83, 83, 89, 91],15,),
    ([62, -34, 10, -28, -42, -12, 4, 20, -20, -84, -76, -16, -44, 26, -78, -40, 50, -10, -56, 76, -88, 24, 64, 10, 64, -8, -68, -42, 26, 24, 62, 36, -68, 8, -68, -2, 8, 38, -18],20,),
    ([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],18,),
    ([23, 14, 44, 29, 93, 56, 22, 29, 97, 71, 43, 72, 74, 8, 92, 40, 18, 34, 78, 79, 93, 63, 79, 44, 35, 72, 88, 83, 40, 89, 66, 66, 54, 56, 44, 62, 72, 94, 79, 79, 24, 55, 72, 37, 27, 55, 16, 58, 83],25,),
    ([-96, -94, -90, -90, -86, -82, -80, -80, -58, -48, -40, -32, -32, -20, -20, -20, -12, -12, -6, -6, -2, 0, 4, 16, 16, 16, 42, 48, 58, 64, 68, 76, 76, 76, 78, 80, 82, 88, 88, 88, 92, 94, 96, 98],27,),
    ([1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 1],34,),
    ([3, 4, 4, 8, 10, 10, 11, 15, 19, 19, 20, 24, 25, 25, 27, 30, 41, 43, 44, 45, 47, 55, 59, 59, 61, 63, 63, 67, 67, 69, 72, 73, 75, 77, 77, 78, 81, 81, 83, 84, 92, 94, 99],31,),
    ([94, -86, 94, 54, -52, 86, 68, 64, 98, 54, -14, -60, -60, -92, 80, -16, 28, 16, -74, 68, 32, -54, 58, -16, -2, -52, -92, -36, 96, -18, 14, 76, 16],26,),
    ([0, 0, 0, 0, 1, 1, 1, 1],7,),
    ([10, 28, 63, 2, 78, 12, 51, 82, 89, 65, 99],8,)
        ]
    n_success = 0
    for i, parameters_set in enumerate(param):
        if f_filled(*parameters_set) == f_gold(*parameters_set):
            n_success+=1
    print("#Results: %i, %i" % (n_success, len(param)))